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Article 551

Recreational Vehicles and Recreational Vehicle Parks

Part I. General

  1. Scope. The provisions of this article cover the electrical conductors and equipment other than low-voltage and automo‐ tive vehicle circuits or extensions thereof, installed within or onrecreational vehicles, the conductors that connect recreational vehicles to a supply of electricity, and the installation of equip‐ ment and devices related to electrical installations within a recreational vehicle park.Informational Note: For information on low-voltage systems, refer to NFPA 1192 -2015, Standard on Recreational Vehicles, and ANSI/RVIA LV-2014, Standard for Low Voltage Systems in Conver‐ sion and Recreational Vehicles.
  2. Definitions. (See Article 100 for additional definitions.)

Air-Conditioning or Comfort-Cooling Equipment. All of that equipment intended or installed for the purpose of processing the treatment of air so as to control simultaneously or individu‐ ally its temperature, humidity, cleanliness, and distribution to meet the requirements of the conditioned space.

Appliance, Fixed. An appliance that is fastened or otherwise secured at a specific location.

Camping Trailer. A vehicular portable unit mounted on wheels and constructed with collapsible partial side walls that fold for towing by another vehicle and unfold at the campsite to provide temporary living quarters for recreational, camping, or travel use. (See Recreational Vehicle.)

Converter. A device that changes electrical energy from one form to another, as from alternating current to direct current.

Dead Front (as applied to switches, circuit breakers, switch‐ boards, and panelboards). Designed, constructed, and instal‐ led so that no current-carrying parts are normally exposed on the front.

Disconnecting Means. The necessary equipment usually consisting of a circuit breaker or switch and fuses, and their accessories, located near the point of entrance of supply conductors in a recreational vehicle and intended to constitute the means of cutoff for the supply to that recreational vehicle.

Frame. Chassis rail and any welded addition thereto of metal thickness of 1.35 mm (0.053 in.) or greater.

Low Voltage. An electromotive force rated 24 volts, nominal, or less.

Motor Home. A vehicular unit designed to provide temporary living quarters for recreational, camping, or travel use built on or permanently attached to a self-propelled motor vehicle chas‐ sis or on a chassis cab or van that is an integral part of the completed vehicle. (See Recreational Vehicle.)

Power-Supply Assembly. The conductors, including ungroun‐ ded, grounded, and equipment grounding conductors, the connectors, attachment plug caps, and all other fittings, grom‐ mets, or devices installed for the purpose of delivering energy from the source of electrical supply to the distribution panel within the recreational vehicle.

Recreational Vehicle. A vehicular-type unit primarily designed as temporary living quarters for recreational, camping, or travel use, which either has its own motive power or is mounted on or drawn by another vehicle.

Informational Note: The basic entities are travel trailer, camping trailer, truck camper, and motor home as referenced in NFPA 1192 -2015, Standard on Recreational Vehicles. See 3.3.46, Recrea‐ tional Vehicle, and A.3.3.46 of NFPA 1192.

Recreational Vehicle Park. Any parcel or tract of land under the control of any person, organization, or governmental entity wherein two or more recreational vehicle, recreational park trailer, and/or other camping sites are offered for use by the public or members of an organization for overnight stays.

Recreational Vehicle Site. A specific area within a recreational vehicle park or campground that is set aside for use by a camp‐ ing unit.

Recreational Vehicle Site Feeder Circuit Conductors. The conductors from the park service equipment to the recrea‐ tional vehicle site supply equipment.

Recreational Vehicle Site Supply Equipment. The necessary equipment, usually a power outlet, consisting of a circuit breaker or switch and fuse and their accessories, located near the point of entrance of supply conductors to a recreational vehicle site and intended to constitute the disconnecting means for the supply to that site.

Recreational Vehicle Stand. That area of a recreational vehicle site intended for the placement of a recreational vehicle.

Travel Trailer. A vehicular unit, mounted on wheels, designed to provide temporary living quarters for recreational, camping, or travel use, of such size or weight as not to require special highway movement permits when towed by a motorized vehi‐ cle, and of gross trailer area less than 30 m2 (320 ft2). (See Recreational Vehicle.)

Truck Camper. A portable unit constructed to provide tempo‐ rary living quarters for recreational, travel, or camping use, consisting of a roof, floor, and sides, designed to be loaded onto and unloaded from the bed of a pickup truck. (See Recrea‐ tional Vehicle.)

551.4 General Requirements.

  1. Not Covered. A recreational vehicle not used for the purposes as defined in 551.2 shall not be required to meet the provisions of Part IV pertaining to the number or capacity of circuits required. It shall, however, meet all other applicable requirements of this article if the recreational vehicle is provi‐ ded with an electrical installation intended to be energized from a 120-volt, 208Y/120-volt, or 120/240-volt, nominal, ac power-supply system.
  2. Systems. This article covers combination electrical systems, generator installations, and 120-volt, 208Y/120-volt, or 120/240-volt, nominal, systems.Informational Note: For information on low-voltage systems, refer to NFPA 1192 -2015, Standard on Recreational Vehicles, and ANSI/RVIA 12V-2011, Standard for Low Voltage Systems in Conver‐ sion and Recreational Vehicles.
  3. Labels. Labels required by Article 551 shall be made of etched, metal-stamped, or embossed brass; stainless steel; plas‐ tic laminates not less than 0.13 mm (0.005 in.) thick; or anodized or alclad aluminum not less than 0.5 mm (0.020 in.) thick or the equivalent.

Informational Note: For guidance on other label criteria used in the recreational vehicle industry, refer to ANSI Z535.4-2011, Product Safety Signs and Labels.

Part II. Combination Electrical Systems

551.20 Combination Electrical Systems.

  1. General. Vehicle wiring suitable for connection to a battery or dc supply source shall be permitted to be connected to a 120-volt source, provided the entire wiring system and equipment are rated and installed in full conformity with Parts I, II, III, IV, and V requirements of this article covering 120-volt electrical systems. Circuits fed from ac transformers shall not supply dc appliances.
  2. Voltage Converters (120-Volt Alternating Current to Low- Voltage Direct Current). The 120-volt ac side of the voltage converter shall be wired in full conformity with the require‐ ments of Parts I, II, and IV of this article for 120-volt electrical systems.Exception: Converters supplied as an integral part of a listed appliance shall not be subject to 551.20(B).All converters and transformers shall be listed for use in recreational vehicles and designed or equipped to provide overtemperature protection. To determine the converter rating, the following percentages shall be applied to the total connected load, including average battery-charging rate, of all 12-volt equipment:The first 20 amperes of load at 100 percent plus The second 20 amperes of load at 50 percent plus All load above 40 amperes at 25 percentException: A low-voltage appliance that is controlled by a momentary switch (normally open) that has no means for holding in the closed position or refrigerators with a 120-volt function shall not be considered as a connected load when determining the required converter rating. Momentarily energized appliances shall be limited to those used to prepare the vehicle for occupancy or travel.
  3. Bonding Voltage Converter Enclosures. The non–current- carrying metal enclosure of the voltage converter shall be connected to the frame of the vehicle with a minimum 8 AWG copper conductor. The voltage converter shall be provided with a separate chassis bonding conductor that shall not be used as a current-carrying conductor.
  4. Dual-Voltage Fixtures, Including Luminaires or Applian‐ ces. Fixtures, including luminaires, or appliances having both 120-volt and low-voltage connections shall be listed for dual voltage.
  5. Autotransformers. Autotransformers shall not be used.
  6. Receptacles and Plug Caps. Where a recreational vehicle is equipped with an ac system, a low-voltage system, or both, receptacles and plug caps of the low-voltage system shall differ in configuration from those of the ac system. Where a vehicle equipped with a battery or other low-voltage system has an external connection for low-voltage power, the connector shall have a configuration that will not accept ac power.

Part III. Other Power Sources

  1. Generator Installations.
    1. Mounting. Generators shall be mounted in such a manner as to be effectively bonded to the recreational vehicle chassis.
    2. Generator Protection. Equipment shall be installed to ensure that the current-carrying conductors from the engine generator and from an outside source are not connected to a vehicle circuit at the same time. Automatic transfer switches in such applications shall be listed for use in one of the following:
      1. Emergency systems
      2. Optional standby systems
      Receptacles used as disconnecting means shall be accessible (as applied to wiring methods) and capable of interrupting their rated current without hazard to the operator.
    3. Installation of Storage Batteries and Generators. Storage batteries and internal-combustion-driven generator units (subject to the provisions of this Code) shall be secured in place to avoid displacement from vibration and road shock.
    4. Ventilation of Generator Compartments. Compartments accommodating internal-combustion-driven generator units shall be provided with ventilation in accordance with instruc‐ tions provided by the manufacturer of the generator unit.Informational Note: For generator compartment construction requirements, see NFPA 1192 -2015, Standard on Recreational Vehicles.
    5. Supply Conductors. The supply conductors from the engine generator to the first termination on the vehicle shall be of the stranded type and be installed in listed flexible conduit or listed liquidtight flexible conduit. The point of first termination shall be in one of the following:
    1. Panelboard
    2. Junction box with a blank cover
    3. Junction box with a receptacle
    4. Enclosed transfer switch
    5. Receptacle assembly listed in conjunction with the gener‐ ator
    The panelboard, enclosed transfer switch, or junction box with a receptacle shall be installed within 450 mm (18 in.) of the point of entry of the supply conductors into the vehicle. A junction box with a blank cover shall be mounted on the compartment wall inside or outside the compartment; to any part of the generator-supporting structure (but not to the generator); to the vehicle floor on the outside of the vehicle; or within 450 mm (18 in.) of the point of entry of the supply conductors into the vehicle. A receptacle assembly listed in conjunction with the generator shall be mounted in accord‐ ance with its listing.
  2. Multiple Supply Source.
    1. Multiple Supply Sources. Where a multiple supply system consisting of an alternate power source and a power-supply cord is installed, the feeder from the alternate power source shall be protected by an overcurrent protective device. Installa‐ tion shall be in accordance with 551.30(A), 551.30(B), and 551.40.
    2. Multiple Supply Sources Capacity. The multiple supply sources shall not be required to be of the same capacity.
    3. Alternate Power Sources Exceeding 30 Amperes. If an alternate power source exceeds 30 amperes, 120 volts, nominal, it shall be permissible to wire it as a 120-volt, nominal, system, a 208Y/120-volt, nominal, system, or a 120/240-volt, nominal, system, provided an overcurrent protective device of the proper rating is installed in the feeder.
    4. Power-Supply Assembly Not Less Than 30 Amperes. The external power-supply assembly shall be permitted to be less than the calculated load but not less than 30 amperes and shall have overcurrent protection not greater than the capacity of the external power-supply assembly.
  3. Other Sources. Other sources of ac power, such as inverters, motor generators, or engine generators, shall be listed for use in recreational vehicles and shall be installed in accordance with the terms of the listing. Other sources of ac power shall be wired in full conformity with the requirements in Parts I, II, III, IV, and V of this article covering 120-volt elec‐ trical systems.
  4. Alternate Source Restrictions. Transfer equipment, if not integral with the listed power source, shall be installed to ensure that the current-carrying conductors from other sources of ac power and from an outside source are not connected to the vehicle circuit at the same time. Automatic transfer switches in such applications shall be listed for use in one of the follow‐ ing:
  1. Emergency systems
  2. Optional standby systems

Part IV. Nominal 120-Volt or 120/240-Volt Systems

  1. 120-Volt or 120/240-Volt, Nominal, Systems.
    1. General Requirements. The electrical equipment and material of recreational vehicles indicated for connection to a wiring system rated 120 volts, nominal, 2-wire with equipment grounding conductor, or a wiring system rated 120/240 volts, nominal, 3-wire with equipment grounding conductor, shall be listed and installed in accordance with the requirements of Parts I, II, III, IV, and V of this article. Electrical equipment connected line-to-line shall have a voltage rating of 208– 230 volts.
    2. Materials and Equipment. Electrical materials, devices, appliances, fittings, and other equipment installed in, intended for use in, or attached to the recreational vehicle shall be listed. All products shall be used only in the manner in which they have been tested and found suitable for the intended use.
    3. Ground-Fault Circuit-Interrupter Protection. The internal wiring of a recreational vehicle having only one 15- or 20-ampere branch circuit as permitted in 551.42(A) and (B) shall have ground-fault circuit-interrupter protection for personnel. The ground-fault circuit interrupter shall be instal‐ led at the point where the power supply assembly terminates within the recreational vehicle. Where a separable cord set is not employed, the ground-fault circuit interrupter shall be permitted to be an integral part of the attachment plug of the power supply assembly. The ground-fault circuit interrupter shall provide protection also under the conditions of an open grounded circuit conductor, interchanged circuit conductors, or both.
  2. Receptacle Outlets Required.
    1. Spacing. Receptacle outlets shall be installed at wall spaces 600 mm (2 ft) wide or more so that no point along the floor line is more than 1.8 m (6 ft), measured horizontally, from an outlet in that space.Exception No. 1: Bath and hallway areas.
      Exception No. 2: Wall spaces occupied by kitchen cabinets, wardrobe cabinets, built-in furniture, behind doors that may open fully against a wall surface, or similar facilities.
    2. Location. Receptacle outlets shall be installed as follows:
      1. Adjacent to countertops in the kitchen [at least one on each side of the sink if countertops are on each side and are 300 mm (12 in.) or over in width and depth].
      2. Adjacent to the refrigerator and gas range space, except where a gas-fired refrigerator or cooking appliance, requiring no external electrical connection, is factory installed.
      3. Adjacent to countertop spaces of 300 mm (12 in.) or more in width and depth that cannot be reached from a receptacle required in 551.41(B)(1) by a cord of 1.8 m (6 ft) without crossing a traffic area, cooking appliance, or sink.
      4. Rooftop decks that are accessible from inside the RV shall have at least one receptacle installed within the perimeter of the rooftop deck. The receptacle shall not be located more than 1.2 m (4 ft) above the balcony, deck, or porch surface. The receptacle shall comply with the require‐ ments of 406.9(B) for wet locations.
    3. Ground-Fault Circuit-Interrupter Protection. Where provided, each 125-volt, single-phase, 15- or 20-ampere recepta‐ cle outlet shall have ground-fault circuit-interrupter protection for personnel in the following locations:
      1. Adjacent to a bathroom lavatory
      2. Where the receptacles are installed to serve the counter‐ top surfaces and are within 1.8 m (6 ft) of any lavatory or sinkException No. 1: Receptacles installed for appliances in dedicated spaces, such as for dishwashers, disposals, refrigerators, freezers, and laundry equipment.Exception No. 2: Single receptacles for interior connections of expanda‐ ble room sections.Exception No. 3: De-energized receptacles that are within 1.8 m (6 ft) of any sink or lavatory due to the retraction of the expandable room section.
      3. In the area occupied by a toilet, shower, tub, or any combination thereof
      4. On the exterior of the vehicle
      Exception: Receptacles that are located inside of an access panel that is installed on the exterior of the vehicle to supply power for an installed appliance shall not be required to have ground-fault circuit-interrupter protection.The receptacle outlet shall be permitted in a listed lumin‐ aire. A receptacle outlet shall not be installed in a tub or combination tub–shower compartment.
    4. Face-Up Position. A receptacle shall not be installed in a face-up position in any countertop or similar horizontal surface.
  3. Branch Circuits Required. Each recreational vehicle containing an ac electrical system shall contain one of the circuit arrangements in 551.42(A) through (D).
    1. One 15-Ampere Circuit. One 15-ampere circuit to supply lights, receptacle outlets, and fixed appliances. Such recrea‐tional vehicles shall be equipped with one 15-ampere switch and fuse or one 15-ampere circuit breaker.
    2. One 20-Ampere Circuit. One 20-ampere circuit to supply lights, receptacle outlets, and fixed appliances. Such recrea‐ tional vehicles shall be equipped with one 20-ampere switch and fuse or one 20-ampere circuit breaker.
    3. Two to Five 15- or 20-Ampere Circuits. Two to five 15- or 20-ampere circuits to supply lights, receptacle outlets, and fixed appliances shall be permitted. Such recreational vehicles shall be permitted to be equipped with panelboards rated 120 volt maximum or 120/240 volt maximum and listed for 30-ampere application supplied by the appropriate power-supply assem‐ blies. Not more than two 120-volt thermostatically controlled appliances shall be installed in such systems unless appliance isolation switching, energy management systems, or similar methods are used.Exception No. 1: Additional 15- or 20-ampere circuits shall be permit‐ ted where a listed energy management system rated at 30-ampere maxi‐ mum is employed within the system.Exception No. 2: Six 15- or 20-ampere circuits shall be permitted with‐ out employing an energy management system, provided that the added sixth circuit serves only the power converter, and the combined load of all six circuits does not exceed the allowable load that was designed for use by the original five circuits.Informational Note: See 210.23(A) for permissible loads. See 551.45(C) for main disconnect and overcurrent protection requirements.
    4. More Than Five Circuits Without a Listed Energy Manage‐ ment System. A 50-ampere, 120/208–240-volt power-supply assembly and a minimum 50-ampere-rated panelboard shall be used where six or more circuits are employed. The load distri‐ bution shall ensure a reasonable current balance between phases.
  4. Branch-Circuit Protection.
    1. Rating. The branch-circuit overcurrent devices shall be rated as follows:
      1. Not more than the circuit conductors, and
      2. Not more than 150 percent of the rating of a single appli‐ ance rated 13.3 amperes or more and supplied by an indi‐ vidual branch circuit, but
      3. Not more than the overcurrent protection size marked on an air conditioner or other motor-operated appliances
    2. Protection for Smaller Conductors. A 20-ampere fuse or circuit breaker shall be permitted for protection for fixtures, including luminaires, leads, cords, or small appliances, and 14 AWG tap conductors, not over 1.8 m (6 ft) long for recessed luminaires.
    3. Fifteen-Ampere Receptacles Considered Protected by
    20 Amperes. If more than one receptacle or load is on a branch circuit, 15-ampere receptacles shall be permitted to be protected by a 20-ampere fuse or circuit breaker.
  5. Power-Supply Assembly. Each recreational vehicle shall have only one of the main power-supply assemblies covered in 551.44(A) through (D).
    1. Fifteen-Ampere Main Power-Supply Assembly. Recrea‐ tional vehicles wired in accordance with 551.42(A) shall use a listed 15-ampere or larger main power-supply assembly.
    2. Twenty-Ampere Main Power-Supply Assembly. Recrea‐ tional vehicles wired in accordance with 551.42(B) shall use a listed 20-ampere or larger main power-supply assembly.
    3. Thirty-Ampere Main Power-Supply Assembly. Recrea‐ tional vehicles wired in accordance with 551.42(C) shall use a listed 30-ampere or larger main power-supply assembly.
    4. Fifty-Ampere Power-Supply Assembly. Recreational vehi‐ cles wired in accordance with 551.42(D) shall use a listed 50- ampere, 120/208–240-volt main power-supply assembly.
  6. Panelboard.
    1. Listed and Appropriately Rated. A listed and appropri‐ ately rated panelboard or other equipment specifically listed for this purpose shall be used. The grounded conductor termi‐ nation bar shall be insulated from the enclosure as provided in 551.54(C). An equipment grounding terminal bar shall be attached inside the enclosure of the panelboard.
    2. Location. The panelboard shall be installed in a readily accessible location with the RV in the setup mode. Working clearance for the panelboard with the RV in the setup mode shall be not less than 600 mm (24 in.) wide and 750 mm (30 in.) deep.Exception No. 1: Where the panelboard cover is exposed to the inside aisle space, one of the working clearance dimensions shall be permitted to be reduced to a minimum of 550 mm (22 in.). A panelboard is considered exposed where the panelboard cover is within 50 mm (2 in.) of the aisle’s finished surface or not more than 25 mm (1 in.) from the backside of doors that enclose the space.Exception No. 2: Compartment doors used for access to a generator shall be permitted to be equipped with a locking system.
    3. Dead-Front Type. The panelboard shall be of the dead- front type and shall consist of one or more circuit breakers or Type S fuseholders. A main disconnecting means shall be provi‐ ded where fuses are used or where more than two circuit break‐ ers are employed. A main overcurrent protective device not exceeding the power-supply assembly rating shall be provided where more than two branch circuits are employed.
  7. Means for Connecting to Power Supply.
    1. Assembly. The power-supply assembly or assemblies shall be factory supplied or factory installed and be of one of the types specified herein.bushings or equivalent. The cord assembly shall have perma‐ nent provisions for protection against corrosion and mechani‐ cal damage while the vehicle is in transit and while the cord assembly is being stored or removed for use.
    2. Cord. The cord exposed usable length shall be measured from the point of entrance to the recreational vehicle or the face of the flanged surface inlet (motor-base attachment plug) to the face of the attachment plug at the supply end.The cord exposed usable length, measured to the point of entry on the vehicle exterior, shall be a minimum of 7.5 m (25 ft) where the point of entrance is at the side of the vehicle or shall be a minimum 9.0 m (30 ft) where the point of entrance is at the rear of the vehicle.Where the cord entrance into the vehicle is more than 900 mm (3 ft) above the ground, the minimum cord lengths above shall be increased by the vertical distance of the cord entrance heights above 900 mm (3 ft).Informational Note: See 551.46(E) for location of point of entrance of a power-supply assembly on the recreational vehicle exterior.
    3. Attachment Plugs.
      1. Units with One 15-Ampere Branch Circuit. Recreational vehicles having only one 15-ampere branch circuit as permitted by 551.42(A) shall have an attachment plug that shall be 2-pole, 3-wire grounding type, rated 15 amperes, 125 volts, conforming to the configuration shown in Figure 551.46(C)(1).Informational Note: Complete details of this configuration can be found in ANSI/NEMA WD 6-2002, Standard for Dimensions of Attachment Plugs and Receptacle, Figure 5.15.
      2. Units with One 20-Ampere Branch Circuit. Recreational vehicles having only one 20-ampere branch circuit as permitted in 551.42(B) shall have an attachment plug that shall be 2-pole,
        Receptacles Caps
        imageGWimageGW125-V, 20-A, 2-pole, 3-wire, grounding type
        imageGW125-V, 15-A, 2-pole, 3-wire,
        1. Separable. Where a separable power-supply assembly consisting of a cord with a female connector and molded attachment plug cap is provided, the vehicle shall be equipped with a permanently mounted, flanged surface inlet (male, recessed-type motor-base attachment plug) wired directly to the panelboard by an approved wiring method. The attachment plug cap shall be of a listed type.20-A, 125-V,2-pole, 3-wire, grounding type
          grounding type
          imageG
          WimageGW
        2. Permanently Connected. Each power-supply assembly shall be connected directly to the terminals of the panelboard or conductors within a junction box and provided with means to prevent strain from being transmitted to the terminals. The ampacity of the conductors between each junction box and the terminals of each panelboard shall be at least equal to the ampacity of the power-supply cord. The supply end of the assembly shall be equipped with an attachment plug of the type described in 551.46(C). Where the cord passes through the walls or floors, it shall be protected by means of conduit and30-A, 125-V, 2-pole, 3-wire, grounding type
          imageGYXWimageGXYW50-A, 125/250-V, 3-pole, 4-wire, grounding type
          FIGURE 551.46(C)(1) Configurations for Grounding-Type Receptacles and Attachment Plug Caps Used for Recreational Vehicle Supply Cords and Recreational Vehicle Lots.
          3-wire grounding type, rated 20 amperes, 125 volts, conforming to the configuration shown in Figure 551.46(C)(1) .Informational Note: Complete details of this configuration can be found in ANSI/NEMA WD 6-2002, National Electrical Manu‐ facturers Association’s Standard for Dimensions of Attachment Plugs and Receptacles, Figure 5.20.
        3. Units with Two to Five 15- or 20-Ampere Branch Circuits. Recreational vehicles wired in accordance with 551.42(C) shall have an attachment plug that shall be 2-pole, 3-wire grounding type, rated 30 amperes, 125 volts, conforming to the configura‐ tion shown in Figure 551.46(C)(1) intended for use with units rated at 30 amperes, 125 volts.Informational Note: Complete details of this configuration can be found in ANSI/NEMA WD 6-2002, National Electrical Manu‐ facturers Association’s Standard for Dimensions of Attachment Plugs and Receptacles, Figure TT.
        4. Units with 50-Ampere Power-Supply Assembly. Recrea‐ tional vehicles having a power-supply assembly rated 50 amperes as permitted by 551.42(D) shall have a 3-pole, 4-wire grounding-type attachment plug rated 50 amperes, 125/250 volts, conforming to the configuration shown in Figure 551.46(C)(1) .Informational Note: Complete details of this configuration can be found in ANSI/NEMA WD 6-2002, Standard for Dimensions of Attachment Plugs and Receptacles, Figure 14.50.
    4. Labeling at Electrical Entrance. Each recreational vehicle shall have a safety label with the signal word WARNING in minimum 6-mm (1∕4-in.) high letters and body text in minimum 3-mm (1∕8-in.) high letters on a contrasting background. The safety label shall be affixed to the exterior skin, at or near the point of entrance of the power-supply cord(s), and shall read, using one of the following warnings, as appropriate:WARNINGTHIS CONNECTION IS FOR 110–125-VOLT AC, 60 HZ,          AMPERE SUPPLY.orTHIS CONNECTION IS FOR 208Y/120-VOLT or 120/240- VOLT AC, 3-POLE, 4-WIRE,60 HZ,               AMPERE SUPPLY.DO NOT EXCEED CIRCUIT RATING. EXCEEDING THE CIRCUIT RATING MAY CAUSE A FIRE AND RESULT IN DEATH OR SERIOUS INJURY.The correct ampere rating shall be marked in the blank space.
    5. Location. The point of entrance of a power-supply assem‐ bly shall be located within 4.5 m (15 ft) of the rear, on the left (road) side or at the rear, left of the longitudinal center of the vehicle, within 450 mm (18 in.) of the outside wall.
    Exception No. 1: A recreational vehicle equipped with only a listed flexi‐ ble drain system or a side-vent drain system shall be permitted to have the electrical point of entrance located on either side, provided the drain(s) for the plumbing system is (are) located on the same side.Exception No. 2: A recreational vehicle shall be permitted to have the electrical point of entrance located more than 4.5 m (15 ft) from the rear. Where this occurs, the distance beyond the 4.5-m (15-ft) dimension shall be added to the cord’s minimum length as specified in 551.46(B).Exception No. 3: Recreational vehicles designed for transporting live‐ stock shall be permitted to have the electrical point of entrance located on either side or the front.
  8. Wiring Methods.
    1. Wiring Systems. Cables and raceways installed in accord‐ ance with Articles 320, 322, 330 through 340, 342 through 362, 386, and 388 shall be permitted in accordance with their appli‐ cable article, except as otherwise specified in this article. An equipment grounding means shall be provided in accordance with 250.118.
    2. Conduit and Tubing. Where rigid metal conduit or inter‐ mediate metal conduit is terminated at an enclosure with a locknut and bushing connection, two locknuts shall be provi‐ ded, one inside and one outside of the enclosure. All cut ends of conduit and tubing shall be reamed or otherwise finished to remove rough edges.
    3. Nonmetallic Boxes. Nonmetallic boxes shall be accepta‐ ble only with nonmetallic-sheathed cable or nonmetallic race‐ ways.
    4. Boxes. In walls and ceilings constructed of wood or other combustible material, boxes and fittings shall be flush with the finished surface or project therefrom.
    5. Mounting. Wall and ceiling boxes shall be mounted in accordance with Article 314.Exception No. 1: Snap-in-type boxes or boxes provided with special wall or ceiling brackets that securely fasten boxes in walls or ceilings shall be permitted.Exception No. 2: A wooden plate providing a 38-mm (11∕2-in.) mini‐ mum width backing around the box and of a thickness of 13 mm (1∕2 in.) or greater (actual) attached directly to the wall panel shall be considered as approved means for mounting outlet boxes.
    6. Raceway and Cable Continuity. Raceways and cable sheaths shall be continuous between boxes and other enclo‐ sures.
    7. Protected. Metal-clad, Type AC, or nonmetallic-sheathed cables and electrical nonmetallic tubing shall be permitted to pass through the centers of the wide side of 2 by 4 wood studs. However, they shall be protected where they pass through 2 by 2 wood studs or at other wood studs or frames where the cable or tubing would be less than 32 mm (11∕4 in.) from the inside or outside surface. Steel plates on each side of the cable or tubing or a steel tube, with not less than 1.35 mm (0.053 in.) wall thickness, shall be installed to protect the cable or tubing. These plates or tubes shall be securely held in place. Where nonmetallic-sheathed cables pass through punched, cut, or drilled slots or holes in metal members, the cable shall be protected by bushings or grommets securely fastened in the opening prior to installation of the cable.
    8. Bends. No bend shall have a radius of less than five times the cable diameter.
    9. Cable Supports. Where connected with cable connectors or clamps, cables shall be secured and supported within 300 mm (12 in.) of outlet boxes, panelboards, and splice boxes on appliances. Supports and securing shall be provided at intervals not exceeding 1.4 m (41∕2 ft) at other places.
    10. Nonmetallic Box Without Cable Clamps. Nonmetallic- sheathed cables shall be secured and supported within 200 mm
      (8 in.) of a nonmetallic outlet box without cable clamps. Where wiring devices with integral enclosures are employed with a loop of extra cable to permit future replacement of the device, the cable loop shall be considered as an integral portion of the device.
    11. Physical Damage. Where subject to physical damage, exposed nonmetallic cable shall be protected by covering boards, guard strips, raceways, or other means.
    12. Receptacle Faceplates. Metal faceplates shall comply with Section 406.5(A). Nonmetallic faceplates shall comply with Section 406.5(C).
    13. Metal Faceplates Grounded. Where metal faceplates are used, they shall be grounded.
    14. Moisture or Physical Damage. Where outdoor or under- chassis wiring is 120 volts, nominal, or over and is exposed to moisture or physical damage, the wiring shall be protected by rigid metal conduit, by intermediate metal conduit, or by elec‐ trical metallic tubing, rigid nonmetallic conduit, or Type MI cable, that is closely routed against frames and equipment enclosures or other raceway or cable identified for the applica‐ tion.
    15. Component Interconnections. Fittings and connectors that are intended to be concealed at the time of assembly shall be listed and identified for the interconnection of building components. Such fittings and connectors shall be equal to the wiring method employed in insulation, temperature rise, and fault-current withstanding and shall be capable of enduring the vibration and shock occurring in recreational vehicles.
    16. Method of Connecting Expandable Units. The method of connecting expandable units to the main body of the vehicle shall comply with 551.47(P)(1) or (P)(2):
      1. Cord-and-Plug-Connected. Cord-and-plug connections shall comply with (a) through (d).
        1. That portion of a branch circuit that is installed in an expandable unit shall be permitted to be connected to the portion of the branch circuit in the main body of the vehicle by means of an attachment plug and cord listed for hard usage. The cord and its connections shall comply with all provisions of Article 400 and shall be considered as a permitted use under 400.10. Where the attachment plug and cord are located within the vehicle’s interior, use of plastic thermoset or elastomer parallel cord Type SPT-3, SP-3, or SPE shall be permitted.
        2. Where the receptacle provided for connection of the cord to the main circuit is located on the outside of the vehicle, it shall be protected with a ground-fault circuit interrupter for personnel and be listed for wet locations. A cord located on the outside of a vehicle shall be identified for outdoor use.
        3. Unless removable or stored within the vehicle inte‐ rior, the cord assembly shall have permanent provisions for protection against corrosion and mechanical damage while the vehicle is in transit.
        4. The attachment plug and cord shall be installed so as not to permit exposed live attachment plug pins.
      2. Direct Wired. That portion of a branch circuit that is installed in an expandable unit shall be permitted to be connected to the portion of the branch circuit in the main body of the vehicle by means of flexible cord installed in accordance with 551.47(P)(2)(a) through (P)(2)(e) or other approved wiring method.
        1. The flexible cord shall be listed for hard usage and for use in wet locations.
        2. The flexible cord shall be permitted to be exposed on the underside of the vehicle.
        3. The flexible cord shall be permitted to pass through the interior of a wall or floor assembly or both a maximum concealed length of 600 mm (24 in.) before terminating at an outlet or junction box.
        4. Where concealed, the flexible cord shall be installed in nonflexible conduit or tubing that is continuous from the outlet or junction box inside the recreational vehicle to a weatherproof outlet box, junction box, or strain relief fitting listed for use in wet locations that is located on the underside of the recreational vehicle. The outer jacket of the flexible cord shall be continuous into the outlet or junction box.
        5. Where the flexible cord passes through the floor to an exposed area inside of the recreational vehicle, it shall be protected by means of conduit and bushings or equivalent.
        Where subject to physical damage, the flexible cord shall be protected with RMC, IMC, Schedule 80 PVC, reinforced ther‐ mosetting resin conduit (RTRC) listed for exposure to physical damage, or other approved means and shall extend at least 150 mm (6 in.) above the floor. A means shall be provided to secure the flexible cord where it enters the recreational vehi‐ cle.
    17. Prewiring for Air-Conditioning Installation. Prewiring installed for the purpose of facilitating future air-conditioning installation shall comply with the applicable portions of this article and the following:
      1. An overcurrent protective device with a rating compatible with the circuit conductors shall be installed in the panel‐ board and wiring connections completed.
      2. The load end of the circuit shall terminate in a junction box with a blank cover or other listed enclosure. Where a junction box with a blank cover is used, the free ends of the conductors shall be adequately capped or taped.
      3. A safety label with the signal word WARNING in minimum 6-mm (1∕4-in.) high letters and body text in minimum 3-mm (1∕8-in.) high letters on a contrasting background shall be affixed on or adjacent to the junc‐ tion box and shall read as follows:WARNINGAIR-CONDITIONING CIRCUIT.THIS CONNECTION IS FOR AIR CONDITIONERS RATED 110–125-VOLT AC, 60 HZ,       AMPERES MAXIMUM.DO NOT EXCEED CIRCUIT RATING. EXCEEDING THE CIRCUIT RATING MAY CAUSE A FIRE AND RESULT IN DEATH OR SERIOUS INJURY.An ampere rating, not to exceed 80 percent of the circuit rating, shall be legibly marked in the blank space.
      4. The circuit shall serve no other purpose.
    18. Prewiring for Generator Installation. Prewiring installed for the purpose of facilitating future generator installation shall comply with the other applicable portions of this article and the following:
      1. Circuit conductors shall be appropriately sized in relation to the anticipated load as stated on the label required in (R)(4).
      2. Where junction boxes are utilized at either of the circuit originating or terminus points, free ends of the conduc‐ tors shall be adequately capped or taped.
      3. Where devices such as receptacle outlet, transfer switch, and so forth, are installed, the installation shall be complete, including circuit conductor connections.
      4. A safety label with the signal word WARNING in mini‐ mum 6-mm (1∕4-in.) high letters and body text in mini‐ mum 3-mm (1∕8-in.) high letters on a contrasting background shall be affixed on the cover of each junction box containing incomplete circuitry and shall read, using one of the following warnings, as appropriate:
      WARNING GENERATORONLY INSTALL A GENERATOR LISTED SPECIFICALLY FOR RV USEHAVING OVERCURRENT PROTECTION RATED 110–125-VOLT AC,60 HZ,              AMPERES MAXIMUM.orGENERATOR ONLY INSTALL A GENERATOR LISTED SPECIFICALLY FOR RV USEHAVING OVERCURRENT PROTECTION RATED 120– 240-VOLT AC,60 HZ,                AMPERES MAXIMUM.The correct ampere rating shall be legibly marked in the blank space.
    19. Prewiring for Other Circuits. Prewiring installed for the purpose of installing other appliances or devices shall comply with the applicable portions of this article and the following:
    1. An overcurrent protection device with a rating compati‐ ble with the circuit conductors shall be installed in the panelboard with wiring connections completed.
    2. The load end of the circuit shall terminate in a junction box with a blank cover or a device listed for the purpose. Where a junction box with blank cover is used, the free ends of the conductors shall be adequately capped or taped.
    3. A safety label with the signal word WARNING in mini‐ mum 6-mm (1∕4-in.) high letters and body text in mini‐ mum 3-mm (1∕8-in.) high letters on a contrasting background shall be affixed on or adjacent to the junc‐ tion box or device listed for the purpose and shall read as follows:
    WARNINGTHIS CONNECTION IS FOR           RATED             VOLT AC, 60 HZ,            AMPERES MAXIMUM. DO NOT EXCEED CIRCUIT RATING.EXCEEDING THE CIRCUIT RATING MAY CAUSE A FIRE AND RESULT IN DEATH ORSERIOUS INJURY.An ampere rating not to exceed 80 percent of the circuit rating shall be legibly marked in the blank space.
  9. Conductors and Boxes. The maximum number of conductors permitted in boxes shall be in accordance with 314.16.
  10. Grounded Conductors. The identification of groun‐ ded conductors shall be in accordance with 200.6.
  11. Connection of Terminals and Splices. Conductor spli‐ ces and connections at terminals shall be in accordance with 110.14.
  12. Switches.
    1. Rating. Switches shall be rated in accordance with 551.51(A)(1) and (A)(2).
      1. Lighting Circuits. For lighting circuits, switches shall be rated not less than 10 amperes, 120–125 volts and in no case less than the connected load.
      2. Motors or Other Loads. Switches for motor or other loads shall comply with the provisions of 404.14.
    2. Location. Switches shall not be installed within wet loca‐ tions in tub or shower spaces unless installed as part of a listed tub or shower assembly.
  13. Receptacles. All receptacle outlets shall be of the grounding type and installed in accordance with 406.4 and 210.21.
  14. Luminaires and Other Equipment.
    1. General. Any combustible wall or ceiling finish exposed between the edge of a canopy or pan of a luminaire or ceiling- suspended (paddle) fan and the outlet box shall be covered with noncombustible material.
    2. Shower Luminaires. If a luminaire is provided over a bathtub or in a shower stall, it shall be of the enclosed and gasketed type and listed for the type of installation, and it shall be ground-fault circuit-interrupter protected.
    3. Outdoor Outlets, Luminaires, Air-Cooling Equipment, and So On. Outdoor luminaires and other equipment shall be listed for outdoor use.
  15. Grounding. (See also 551.56 on bonding of non– current-carrying metal parts.)
    1. Power-Supply Grounding. The grounding conductor in the supply cord or feeder shall be connected to the grounding bus or other approved grounding means in the panelboard.
    2. Panelboard. The panelboard shall have a grounding bus with terminals for all grounding conductors or other approved grounding means.
    3. Insulated Grounded Conductor (Neutral Conductor). The grounded circuit conductor (neutral conductor) shall be insulated from the equipment grounding conductors and from equipment enclosures and other grounded parts. The groun‐ ded circuit conductor (neutral conductor) terminals in the panelboard and in ranges, clothes dryers, counter-mounted cooking units, and wall-mounted ovens shall be insulated from the equipment enclosure. Bonding screws, straps, or buses in the panelboard or in appliances shall be removed and discar‐ ded. Connection of electric ranges and electric clothes dryers utilizing a grounded conductor, if cord-connected, shall be made with 4-conductor cord and 3-pole, 4-wire grounding-type plug caps and receptacles.
  16. Interior Equipment Grounding.
    1. Exposed Metal Parts. In the electrical system, all exposed metal parts, enclosures, frames, luminaire canopies, and so forth, shall be effectively bonded to the grounding terminals or enclosure of the panelboard.
    2. Equipment Grounding and Bonding Conductors. Bare wires, insulated wire with an outer finish that is green or green with one or more yellow stripes, shall be used for equipment grounding or bonding conductors only.
    3. Grounding of Electrical Equipment. Grounding of electri‐ cal equipment shall be accomplished by one or more of the following methods:
      1. Connection of metal raceway, the sheath of Type MC and Type MI cable where the sheath is identified for ground‐ ing, or the armor of Type AC cable to metal enclosures.
      2. A connection between the one or more equipment grounding conductors and a metal enclosure by means of a grounding screw, which shall be used for no other purpose, or a listed grounding device.
      3. The equipment grounding conductor in nonmetallic- sheathed cable shall be permitted to be secured under a screw threaded into the luminaire canopy other than a mounting screw or cover screw, or attached to a listed grounding means (plate) in a nonmetallic outlet box for luminaire mounting. [Grounding means shall also be permitted for luminaire attachment screws.]
    4. Grounding Connection in Nonmetallic Box. A connec‐ tion between the one or more equipment grounding conduc‐ tors brought into a nonmetallic outlet box shall be so arranged that a connection of the equipment grounding conductor can be made to any fitting or device in that box that requires grounding.
    5. Grounding Continuity. Where more than one equipment grounding or bonding conductor of a branch circuit enters a box, all such conductors shall be in good electrical contact with each other, and the arrangement shall be such that the discon‐ nection or removal of a receptacle, luminaire, or other device fed from the box will not interfere with or interrupt the grounding continuity.
    6. Cord-Connected Appliances. Cord-connected appliances, such as washing machines, clothes dryers, refrigerators, and the electrical system of gas ranges, and so forth, shall be grounded by means of an approved cord with equipment grounding conductor and grounding-type attachment plug.
  17. Bonding of Non–Current-Carrying Metal Parts.
    1. Required Bonding. All exposed non–current-carrying metal parts that are likely to become energized shall be effec‐ tively bonded to the grounding terminal or enclosure of the panelboard.
    2. Bonding Chassis. A bonding conductor shall be connec‐ ted between any panelboard and an accessible terminal on the chassis. Aluminum or copper-clad aluminum conductors shall not be used for bonding if such conductors or their terminals are exposed to corrosive elements.Exception: Any recreational vehicle that employs a unitized metal chassis-frame construction to which the panelboard is securely fastened with a bolt(s) and nut(s) or by welding or riveting shall be considered to be bonded.
    3. Bonding Conductor Requirements. Grounding terminals shall be of the solderless type and listed as pressure terminal connectors recognized for the wire size used. The bonding conductor shall be solid or stranded, insulated or bare, and shall be 8 AWG copper minimum, or equal.
    4. Metallic Roof and Exterior Bonding. The metal roof and exterior covering shall be considered bonded where both of the following conditions apply:
      1. The metal panels overlap one another and are securely attached to the wood or metal frame parts by metal fasteners.
      2. The lower panel of the metal exterior covering is secured by metal fasteners at each cross member of the chassis, or the lower panel is connected to the chassis by a metal strap.
    5. Gas, Water, and Waste Pipe Bonding. The gas, water, and waste pipes shall be considered grounded if they are bonded to the chassis.
    6. Furnace and Metal Air Duct Bonding. Furnace and metal circulating air ducts shall be bonded.
  18. Appliance Accessibility and Fastening. Every appliance shall be accessible for inspection, service, repair, and replace‐ ment without removal of permanent construction. Means shall be provided to securely fasten appliances in place when the recreational vehicle is in transit.

Part V. Factory Tests

551.60 Factory Tests (Electrical). Each recreational vehicle designed with a 120-volt or a 120/240-volt electrical system shall withstand the applied voltage without electrical break‐ down of a 1-minute, 900-volt ac or 1280-volt dc dielectric strength test, or a 1-second, 1080-volt ac or 1530-volt dc dielec‐ tric strength test, with all switches closed, between ungrounded and grounded conductors and the recreational vehicle ground. During the test, all switches and other controls shall be in the “on” position. Fixtures, including luminaires and permanently installed appliances, shall not be required to withstand this test. The test shall be performed after branch circuits are complete prior to energizing the system and again after all outer cover‐ ings and cabinetry have been secured. The dielectric test shall be performed in accordance with the test equipment manufac‐ turer’s written instructions.

Each recreational vehicle shall be subjected to all of the following:

  1. A continuity test to ensure that all metal parts are prop‐ erly bonded
  2. Operational tests to demonstrate that all equipment is properly connected and in working order
  3. Polarity checks to determine that connections have been properly made
  4. GFCI test to demonstrate that the ground fault protection device(s) installed on the recreational vehicle are operat‐ ing properly

Part VI. Recreational Vehicle Parks

  1. Type Receptacles Provided.
    1. 20-Ampere. Every recreational vehicle site with electrical supply shall be equipped with recreational vehicle site supply equipment with at least one 20-ampere, 125-volt receptacle.
    2. 30-Ampere. A minimum of 70 percent of all recreational vehicle sites with electrical supply shall each be equipped with a 30-ampere, 125-volt receptacle conforming to Figure
      551.46(C)(1). This supply shall be permitted to include addi‐ tional receptacle configurations conforming to 551.81. The remainder of all recreational vehicle sites with electrical supply shall be equipped with one or more of the receptacle configu‐ rations conforming to 551.81.
    3. 50-Ampere. A minimum of 20 percent of existing and 40 percent of all new recreational vehicle sites, with electrical supply, shall each be equipped with a 50-ampere, 125/250-volt receptacle conforming to the configuration as identified in Figure 551.46(C)(1). Every recreational vehicle site equipped with a 50-ampere receptacle shall also be equipped with a 30- ampere, 125-volt receptacle conforming to Figure 551.46(C)(1). These electrical supplies shall be permitted to include additional receptacles that have configurations in accordance with 551.81.
    4. Tent Sites. Dedicated tent sites with a 15- or 20-ampere electrical supply shall be permitted to be excluded when deter‐ mining the percentage of recreational vehicle sites with 30- or 50-ampere receptacles.
    5. Additional Receptacles. Additional receptacles shall be permitted for the connection of electrical equipment outside the recreational vehicle within the recreational vehicle park.
    6. GFCI Protection. All 125-volt, single-phase, 15- and 20-ampere receptacles shall have listed ground-fault circuit- interrupter protection for personnel. The GFCI devices used in RV site electrical equipment shall not be required to be weather or tamper resistant in accordance with 406.9 and 406.12.
    Informational Note: The percentage of 50 ampere sites required by 551.71 could be inadequate for seasonal recreational vehicle sites serving a higher percentage of recreational vehicles with 50 ampere electrical systems. In that type of recreational vehicle park, the percentage of 50 ampere sites could approach 100 percent.
  2. Distribution System.imageN
    1. Systems. Distribution systems shall provide the voltage and have a capacity for the receptacles provided in the recrea‐ tional vehicle (RV) site supply equipment as calculated accord‐ ing to 551.73 and shall have an ampacity not less than30 amperes. Systems permitted include 120 volts, 1-phase; 120/240 volts, 1-phase; and 120/208 volts, 1-phase.imageN
    2. Three-Phase Systems. Feeders from 208Y/120-volt, 3- phase systems shall be permitted to include two ungrounded

    Informational Note: Due to the long circuit lengths typical inmost recreational vehicle parks, feeder conductor sizes found in the ampacity tables of Article 310 may be inadequate to main‐ tain the voltage regulation suggested in 215.2(A)(1) Informa‐ tional Note No. 2. Total circuit voltage drop is a sum of the voltage drops of each serial circuit segment, where the load for each segment is calculated using the load that segment sees and the demand factors shown in Table 551.73(A).
  3. Calculated Load.
  4. Basis of Calculations. Electrical services and feeders shall be calculated on the basis of not less than 12,000 volt-amperes per site equipped with 50-ampere, 208Y/120 or 120/240-volt supply facilities; 3600 volt-amperes per site equipped with both 20-ampere and 30-ampere supply facilities; 2400 volt-amperes per site equipped with only 20-ampere supply facilities; and 600 volt-amperes per site equipped with only 20-ampere supply facilities that are dedicated to tent sites. The demand factors set forth in Table 551.73(A) shall be the minimum allowable demand factors that shall be permitted in calculating load for service and feeders. Where the electrical supply for a recrea‐ tional vehicle site has more than one receptacle, the calculated load shall be calculated only for the highest rated receptacle.Where the electrical supply is in a location that serves two recreational vehicles, the equipment for both sites shall comply with 551.77, and the calculated load shall only be calculated for the two receptacles with the highest rating.
    • (B) Demand Factors. The demand factor for a given numberof sites shall apply to all sites indicated. For example, 20 sites calculated at 45 percent of 3600 volt-amperes results in a permissible demand of 1620 volt-amperes per site or a total of 32,400 volt-amperes for 20 sites.Informational Note: These demand factors may be inadequate in areas of extreme hot or cold temperature with loaded circuits for heating or air conditioning.Loads for other amenities such as, but not limited to, service buildings, recreational buildings, and swimming pools shall be calculated separately and then be added to the value calculated for the recreational vehicle sites where they are all supplied by a common service.
    • 551.74 Overcurrent Protection. Overcurrent protection shallbe provided in accordance with Article 240.
      Table 551.73(A) Demand Factors for Site Feeders and Service- Entrance Conductors for Park Sitesconductors and shall include one grounded conductor and                                                                                                                                one equipment grounding conductor. So far as practicable, the loads shall be equally distributed on the 3-phase system.Number of Recreational Vehicle SitesDemand Factor (%)
      1. Receptacles. Receptacles rated at 50 amperes shall be supplied from a branch circuit of the voltage class and rating of the receptacle. Other recreational vehicle sites with 125-volt, 20- and 30-ampere receptacles shall be permitted to be derived from any grounded distribution system that supplies 120-volt, single-phase power. The neutral conductors shall not be reduced in size below the size of the ungrounded conductors for the site distribution.
      2. Neutral Conductors. Neutral conductors shall be permit‐ ted to be reduced in size below the minimum required size of the ungrounded conductors for 240-volt, line-to-line, perma‐ nently connected loads only.
image

1 100

2 90

3 80

4 75

5 65

6 60

7–9 55

10–12 50

13–15 48

16–18 47

19–21 45

22–24 43

25–35 42

36 plus 41

551.75 Grounding.

  1. General. All electrical equipment and installations in recreational vehicle parks shall be grounded as required by Article 250.imageN•
  2. Grounding Electrode. Power outlets or recreational vehi‐

cle site supply equipment, other than those used as service equipment, shall not be required to have a grounding elec‐ trode. An auxiliary grounding electrode(s) in accordance with

250.54 shall be permitted to be installed.

  1. Grounding — Recreational Vehicle Site Supply Equip‐ ment.
    1. Exposed Non–Current-Carrying Metal Parts. Exposed non–current-carrying metal parts of fixed equipment, metal boxes, cabinets, and fittings that are not electrically connected to grounded equipment shall be grounded by an equipment grounding conductor run with the circuit conductors from the service equipment or from the transformer of a secondary distribution system. Equipment grounding conductors shall be sized in accordance with 250.122 and shall be permitted to be spliced by listed means.The arrangement of equipment grounding connections shall be such that the disconnection or removal of a receptacle or other device will not interfere with, or interrupt, the grounding continuity.
    2. Secondary Distribution System. Each secondary distribu‐ tion system shall be grounded at the transformer.
    3. Grounded Conductor Not to Be Used as an Equipment Ground. The grounded conductor shall not be used as an equipment grounding conductor for recreational vehicles or equipment within the recreational vehicle park.
    4. No Connection on the Load Side. No connection to a grounding electrode shall be made to the grounded conductor on the load side of the service disconnecting means except as covered in 250.30(A) for separately derived systems, and 250.32(B) Exception No. 1 for separate buildings.
  2. Recreational Vehicle Site Supply Equipment.
  1. Location. Where provided on back-in sites, the recrea‐ tional vehicle site electrical supply equipment shall be located on the left (road) side of the parked vehicle, on a line that is1.5 m to 2.1 m (5 ft to 7 ft) from the left edge (driver’s side of the parked RV) of the stand and shall be located at any point on this line from the rear of the stand to 4.5 m (15 ft) forward of the rear of the stand.For pull-through sites, the electrical supply equipment shall be permitted to be located at any point along the line that is1.5 m to 2.1 m (5 ft to 7 ft) from the left edge (driver’s side of the parked RV) from 4.9 m (16 ft) forward of the rear of the stand to the center point between the two roads that gives access to and egress from the pull-through sites.The left edge (driver’s side of the parked RV) of the stand shall be marked.
  2. Disconnecting Means. A disconnecting switch or circuit breaker shall be provided in the site supply equipment for disconnecting the power supply to the recreational vehicle.
  3. Access. All site supply equipment shall be accessible by an unobstructed entrance or passageway not less than 600 mm (2 ft) wide and 2.0 m (6 ft 6 in.) high.
  4. Mounting Height. Site supply equipment shall be located not less than 600 mm (2 ft) or more than 2.0 m (6 ft 6 in.) above the ground.
  5. Working Space. Sufficient space shall be provided and maintained about all electrical equipment to permit ready and safe operation, in accordance with 110.26.
  6. Marking. Where the site supply equipment contains a 125/250-volt receptacle, the equipment shall be marked as follows: “Turn disconnecting switch or circuit breaker off before inserting or removing plug. Plug must be fully inserted or removed.” The marking shall be located on the equipment adjacent to the receptacle outlet.
  1. Protection of Outdoor Equipment.
    1. Wet Locations. All switches, circuit breakers, receptacles, control equipment, and metering devices located in wet loca‐ tions shall be weatherproof.
    2. Meters. If secondary meters are installed, meter sockets without meters installed shall be blanked off with an approved blanking plate.
  2. Clearance for Overhead Conductors. Open conduc‐ tors of not over 1000 volts, nominal, shall have a vertical clear‐ ance of not less than 5.5 m (18 ft) and a horizontal clearance of not less than 900 mm (3 ft) in all areas subject to recrea‐ tional vehicle movement. In all other areas, clearances shall conform to 225.18 and 225.19.Informational Note: For clearances of conductors over 600 volts, nominal, see 225.60 and 225.61.
  3. Underground Service, Feeder, Branch-Circuit, and Recreational Vehicle Site Feeder-Circuit Conductors.
    1. General. All direct-burial conductors, including the equipment grounding conductor if of aluminum, shall be insu‐ lated and identified for the use. All conductors shall be contin‐ uous from equipment to equipment. All splices and taps shall be made in approved junction boxes or by use of listed mate‐ rial.
    2. Protection Against Physical Damage. Direct-buried conductors and cables entering or leaving a trench shall be protected by rigid metal conduit, intermediate metal conduit, electrical metallic tubing with supplementary corrosion protec‐ tion, rigid polyvinyl chloride conduit (PVC), nonmetallic underground conduit with conductors (NUCC), high density polyethylene conduit (HDPE), reinforced thermosetting resin conduit (RTRC), liquidtight flexible nonmetallic conduit, liquidtight flexible metal conduit, or other approved raceways or enclosures. Where subject to physical damage, the conduc‐ tors or cables shall be protected by rigid metal conduit, inter‐ mediate metal conduit, Schedule 80 PVC conduit, or RTRC listed for exposure to physical damage. All such protection shall extend at least 450 mm (18 in.) into the trench from finished grade.
    Informational Note: See 300.5 and Article 340 for conductors or Type UF cable used underground or in direct burial in earth.
  4. Receptacles. A receptacle to supply electric power to a recreational vehicle shall be one of the configurations shown in Figure 551.46(C)(1) in the following ratings:
  1. 50-ampere — 125/250-volt, 50-ampere, 3-pole, 4-wire grounding type for 120/240-volt systems
  2. 30-ampere — 125-volt, 30-ampere, 2-pole, 3-wire ground‐ ing type for 120-volt systems
  3. 20-ampere — 125-volt, 20-ampere, 2-pole, 3-wire ground‐ ing type for 120-volt systems

Informational Note: Complete details of these configurations can be found in ANSI/NEMA WD 6-2002, National Electrical Manufacturers Association’s Standard for Dimensions of Attachment Plugs and Receptacles, Figures 14-50, TT, and 5-20.

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